Report task CPU usage through the cpuacct cgroup controller.

PiperOrigin-RevId: 366923274

1 files changed, 77 insertions, 2 deletions

diff --git a/pkg/sentry/fsimpl/cgroupfs/cpuacct.go b/pkg/sentry/fsimpl/cgroupfs/cpuacct.go
index 0bb7f5c76..d4104a00e 100644
--- a/pkg/sentry/fsimpl/cgroupfs/cpuacct.go
+++ b/pkg/sentry/fsimpl/cgroupfs/cpuacct.go
@@ -15,9 +15,14 @@
 package cgroupfs
 
 import (
+	"bytes"
+	"fmt"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/usage"
 )
 
 // +stateify savable
@@ -34,6 +39,76 @@ func newCPUAcctController(fs *filesystem) *cpuacctController {
 }
 
 // AddControlFiles implements controller.AddControlFiles.
-func (c *cpuacctController) AddControlFiles(ctx context.Context, creds *auth.Credentials, _ *cgroupInode, contents map[string]kernfs.Inode) {
-	// This controller is currently intentionally empty.
+func (c *cpuacctController) AddControlFiles(ctx context.Context, creds *auth.Credentials, cg *cgroupInode, contents map[string]kernfs.Inode) {
+	cpuacctCG := &cpuacctCgroup{cg}
+	contents["cpuacct.stat"] = c.fs.newControllerFile(ctx, creds, &cpuacctStatData{cpuacctCG})
+	contents["cpuacct.usage"] = c.fs.newControllerFile(ctx, creds, &cpuacctUsageData{cpuacctCG})
+	contents["cpuacct.usage_user"] = c.fs.newControllerFile(ctx, creds, &cpuacctUsageUserData{cpuacctCG})
+	contents["cpuacct.usage_sys"] = c.fs.newControllerFile(ctx, creds, &cpuacctUsageSysData{cpuacctCG})
+}
+
+// +stateify savable
+type cpuacctCgroup struct {
+	*cgroupInode
+}
+
+func (c *cpuacctCgroup) collectCPUStats() usage.CPUStats {
+	var cs usage.CPUStats
+	c.fs.tasksMu.RLock()
+	// Note: This isn't very accurate, since the tasks are potentially
+	// still running as we accumulate their stats.
+	for t := range c.ts {
+		cs.Accumulate(t.CPUStats())
+	}
+	c.fs.tasksMu.RUnlock()
+	return cs
+}
+
+// +stateify savable
+type cpuacctStatData struct {
+	*cpuacctCgroup
+}
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *cpuacctStatData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	cs := d.collectCPUStats()
+	fmt.Fprintf(buf, "user %d\n", linux.ClockTFromDuration(cs.UserTime))
+	fmt.Fprintf(buf, "system %d\n", linux.ClockTFromDuration(cs.SysTime))
+	return nil
+}
+
+// +stateify savable
+type cpuacctUsageData struct {
+	*cpuacctCgroup
+}
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *cpuacctUsageData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	cs := d.collectCPUStats()
+	fmt.Fprintf(buf, "%d\n", cs.UserTime.Nanoseconds()+cs.SysTime.Nanoseconds())
+	return nil
+}
+
+// +stateify savable
+type cpuacctUsageUserData struct {
+	*cpuacctCgroup
+}
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *cpuacctUsageUserData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	cs := d.collectCPUStats()
+	fmt.Fprintf(buf, "%d\n", cs.UserTime.Nanoseconds())
+	return nil
+}
+
+// +stateify savable
+type cpuacctUsageSysData struct {
+	*cpuacctCgroup
+}
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *cpuacctUsageSysData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	cs := d.collectCPUStats()
+	fmt.Fprintf(buf, "%d\n", cs.SysTime.Nanoseconds())
+	return nil
 }